Let’s talk about immigration in this current frenzy about keeping Syrian refugees out.

DAESH (ISIS) or al Qaeda used EU citizens to damage Paris. They will try to use Americans here. Some Americans have gone over to the dark side, trained abroad, could return and blend in here. That is a similar problem with deporting those undocumented people who have spent most of their lives here – in their countries of origin many have no ties, job history, knowledge of the culture or the environment. Deported, they are valuable to smugglers who use them to get contraband across our borders. Allowed to stay, they could be productive members of society. For Americans and immigrants alike, keeping people working at decent jobs is the best way to keep everyone out of trouble.

Population also affects national power, what we can produce, and the power we project. That is important in an increasingly dangerous world. Adding to the workforce and as consumers, immigrants increase the size and health of our economy, and instead of straining our budget, they help to sustain our social safety net, as many aging countries have been finding out.

Immigration is not without costs, however. China and India now each have over a billion people. India’s population has tripled since I was young. These are population explosions. Chinese authorities understood that China could not sustain population growth and slowed it precipitously.

Moving people from places where they live in fear to an America where they can live in peace and prosperity is neutral with respect to worldwide population. But it may do environmental damage if it means changing to an environmentally more destructive lifestyle. That makes it doubly important to control, limit and reduce environmental damage. It means that we should, must, continue to invest in ways to reduce our use of fossil fuels, and increase our use of solar and wind energy and passive solar heating. We must control our overuse of water, and invest in better ways to use it. We need to rethink our national land-use policies – it makes little sense to irrigate deserts for farmland and build suburbs on productive lands. We are shifting farmland from places that have plenty of water to those that don’t. That is not only wasteful, it also leads to drought, salinization of the land, and makes other settled places unlivable, save at the enormous cost of desalinization of seawater.

Ultimately both our goals for immigration and our goals for America, our children and grandchildren must be driven by concern for the people who will inhabit it. That means care and concern for the immigrants themselves, and care for everyone, those we are strongly attached to and all the people of the earth, expressed through environmental policies that can keep the earth habitable. In that effort we all have to be willing to share and accept effective regulation. There is no other way.

And yes, protecting the lives of our children and grandchildren requires some sacrifice. But aren’t the sacrifices we make for those we deeply care about one of the most satisfying things we get to do? All our faiths confirm those duties and affirm the joy of giving and caring. It’s hard to think of people as deserving who are unwilling to share in the general sacrifices for their and our offspring.

— This commentary was broadcast on WAMC Northeast Report, April 5, 2016.